A high speed sensor system for tactile interaction research

Schürmann C. A high speed sensor system for tactile interaction research. Bielefeld: Bielefeld University Library; 2013.In this work we will describe and implement the first tactile sensor system that combines the properties of modularity with a very high sensing speed, a high sensitivity and a high spatial resolution. This unique combination of features enables researchers to develop novel applications and makes it possible to replace task specific tactile sensors with a single system. The very high sensing speed of the system allows for slip detection during robot grasping. And as all our sensor cells are sampled with the same high frequency, our system can even enable the slip detection for multiple contact points at the same time. This high speed was made possible through the development of a highly integrated parallel sensor sampling architecture. The modularity of the system allows it to be employed in a multitude of applications. Tactile sensitive surfaces of various dimensions can be easily realized through a very simple ’plug and use’ principle without the need for software configuration by the user. This was made possible by developing a new bus system that allows the relative localization of the participants. Our system can be used to create tactile sensitive table surfaces with a large amount of sensor cells and due to its high speed design still provide for real time frame rates. The flexibility and high performance of the system enabled us to develop a tactile sensitive object that allows the continuous high speed monitoring of human finger forces. For this we solved the problem of integrating the tactile sensors to allow free movement of the object, while maintaining a constant high rate of data capture and realizing a low latency synchronization to external devices. The high sensitivity of the system was made possible through technical innovation in the state of the art of resistive based tactile sensors. We did so by creating an optimized sensor cell shape and investigating the behavior of different sensor materials. The knowledge gained in this process was further used to advance the existing method of sensor normalization into a real time method. We will present a range of tactile interaction scenarios that have been realized with the tactile sensor system named Myrmex. These scenarios include the investigating of human grasp force control during a pick and place task, a tactile table for integration into an intelligent household and a tactile table for the manipulation of virtual clay as a form of finger training. In addition we will present a selection of scenarios where the Myrmex system was employed by other researchers, as in using the sensor modules as (large) tactile fingertips on robot arms to implement tactile servoing or slip detection during object grasping. The system has also been used to study human finger forces as well as investigating novel methods for prosthesis control. The positive results from all the scenarios support our conclusion that the developed Myrmex system is a very valuable and reliable tool for the research of tactile interactions

A multisensing setup for the intelligent tire monitoring

The present paper offers the chance to experimentally measure, for the first time, the internal tire strain by optical fiber sensors during the tire rolling in real operating conditions. The phenomena that take place during the tire rolling are in fact far from being completely understood. Despite several models available in the technical literature, there is not a correspondently large set of experimental observations. The paper includes the detailed description of the new multi-sensing technology for an ongoing vehicle measurement, which the research group has developed in the context of the project OPTYRE. The experimental apparatus is mainly based on the use of optical fibers with embedded Fiber Bragg Gratings sensors for the acquisition of the circumferential tire strain. Other sensors are also installed on the tire, such as a phonic wheel, a uniaxial accelerometer, and a dynamic temperature sensor. The acquired information is used as input variables in dedicated algorithms that allow the identification of key parameters, such as the dynamic contact patch, instantaneous dissipation and instantaneous grip. The OPTYRE project brings a contribution into the field of experimental grip monitoring of wheeled vehicles, with implications both on passive and active safety characteristics of cars and motorbikes

High Accuracy Fuel Flowmeter, Phase 1

Technology related to aircraft fuel mass - flowmeters was reviewed to determine what flowmeter types could provide 0.25%-of-point accuracy over a 50 to one range in flowrates. Three types were selected and were further analyzed to determine what problem areas prevented them from meeting the high accuracy requirement, and what the further development needs were for each. A dual-turbine volumetric flowmeter with densi-viscometer and microprocessor compensation was selected for its relative simplicity and fast response time. An angular momentum type with a motor-driven, spring-restrained turbine and viscosity shroud was selected for its direct mass-flow output. This concept also employed a turbine for fast response and a microcomputer for accurate viscosity compensation. The third concept employed a vortex precession volumetric flowmeter and was selected for its unobtrusive design. Like the turbine flowmeter, it uses a densi-viscometer and microprocessor for density correction and accurate viscosity compensation

Micro-Electro-Mechanical-Systems (MEMS) and Fluid Flows

The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electro-mechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for flow control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale configurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas flows experience large Knudsen numbers, and therefore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-science research

Tactile on-chip pre-processing with techniques from artificial retinas

The interest in tactile sensors is increasing as their use in complex unstructured environments is demanded, like in tele-presence, minimal invasive surgery, robotics etc. The matrix of pressure data these devices provide can be managed with many image processing algorithms to extract the required information. However, as in the case of vision chips or artificial retinas, problems arise when the array size and the computation complexity increase. Having a look to the skin, the information collected by every mechanoreceptor is not carried to the brain for its processing, but some complex pre-processing is performed to fit the limited throughput of the nervous system. This is specially important for high bandwidth demanding tasks. Experimental works report that neural response of skin mechanoreceptors encodes the change in local shape from an offset level rather than the absolute force or pressure distributions. This is also the behavior of the retina, which implements a spatio-temporal averaging. We propose the same strategy in tactile preprocessing, and we show preliminary results when it faces the detection of the slip, which involves fast real-time processing.Ministerio de Ciencia y Tecnología TIC2003 - 09817-C0

Safety Relevant Positioning Applications in Rail Traffic using the European Satellite System "Galileo"

Die Ortung im Eisenbahnverkehr hat eine hohe sicherheitstechnische Relevanz. Eine falsch detektierte Position eines Fahrzeugs kann zu einer erheblichen Gefährdung führen, da die ermittelte Ortsinformation für die Freigabe und das Wiederbesetzen von Gleisabschnitten genutzt wird. Daraus abgeleitet, müssen Ortungssysteme bei der Zulassung unter anderem die folgenden sicherheitskritischen Anforderungen erfüllen Genauigkeit, Zuverlässigkeit, Integrität und Verfügbarkeit der Ortungsinformation, die gemäß SIL 4 nachzuweisen sind

Automatic Recognition of Light Microscope Pollen Images

This paper is a progress report on a project aimed at the realization of a low-cost, automatic, trainable system "AutoStage" for recognition and counting of pollen. Previous work on image feature selection and classification has been extended by design and integration of an XY stage to allow slides to be scanned, an auto focus system, and segmentation software. The results of a series of classification tests are reported, and verified by comparison with classification performance by expert palynologists. A number of technical issues are addressed, including pollen slide preparation and slide sampling protocols

On line estimation of rolling resistance for intelligent tires

The analysis of a rolling tire is a complex problem of nonlinear elasticity. Although in the technical literature some tire models have been presented, the phenomena involved in the tire rolling are far to be completely understood. In particular, small knowledge comes even from experimental direct observation of the rolling tire, in terms of dynamic contact patch, instantaneous dissipation due to rubber-road friction and hysteretic behavior of the tire structure, and instantaneous grip. This paper illustrates in details a new powerful technology that the research group has developed in the context of the project OPTYRE. A new wireless optical system based on Fiber Bragg Grating strain sensors permits a direct observation of the inner tire stress when rolling in real conditions on the road. From this information, following a new suitably developed tire model, it is possible to identify the instant area of the contact patch, the grip conditions as well the instant dissipation, which is the object of the present work